The serotonin transporter (SERT) and other monoamine transporters operate in either a forward transport mode, where the transporter undergoes a full transport cycle, or an exchange mode, where the transporter seesaws through half-cycles. Amphetamines trigger the exchange-mode leading to substrate efflux. This efflux was proposed to rely on the N-terminus, which was suggested to adopt different conformations in the inward-, outward-facing and amphetamine-bound states. This prediction was verified by tryptic digestion of SERT-expressing membranes: in the absence of Na+, the N-terminus was rapidly digested. Amphetamine conferred protection against cleavage suggesting a relay between the conformational states of the hydrophobic core and the N-terminus. We searched for a candidate segment, which supported the conformational switch, by serial truncation removing 22 (ΔN22), 32 (ΔN32) or 42 (ΔN42) N-terminal residues. This did not affect surface expression, inhibitor binding and substrate influx. However, amphetamine-induced efflux by SERT-ΔN32 or SERT-ΔN42 (but not by SERT-ΔN22) was markedly diminished. We examined the individual steps in the transport cycle by recording transporter-associated currents: The recovery rate of capacitive peak - but not of steady-state - currents was significantly lower for SERT-ΔN32 than that of wild-type SERT and SERT-ΔN22. Thus, the exchange mode of SERT-ΔN32 was selectively impaired. Our observations show that the N-terminus affords the switch between transport modes. The findings are consistent with a model, where the N-terminus acts as a lever to support amphetamine-induced efflux by SERT.
from #AlexandrosSfakianakis via Alexandros G.Sfakianakis on Inoreader http://ift.tt/2jeoGDl
via IFTTT
Εγγραφή σε:
Σχόλια ανάρτησης (Atom)
Δημοφιλείς αναρτήσεις
-
Publication date: Available online 4 January 2018 Source: European Journal of Radiology Author(s): Peiyao Zhang, Jing Wang, Qin Xu, Zhen...
-
Medicine by Alexandros G. Sfakianakis,Anapafseos 5 Agios Nikolaos 72100 Crete Greece,00302841026182, Butyric Acid from Probiotic Staphyloco...
-
Does CBD Oil Lower Blood Pressure? This article was originally published at SundayScaries." Madeline Taylor POSTED ON January 13, 20...
-
Medicine by Alexandros G. Sfakianakis,Αλέξανδρος Γ. Σφακιανάκης A Novel Technique for Endoscopic Repair of Large Anterior Skull Base Defect...
-
2016-11-22T07-55-59Z Source: International Journal of Medical Science and Public Health Banothu Srinivas, Madhu Mohan Reddy B. Backgrou...
-
2016-10-15T06-30-01Z Source: The Southeast Asian Journal of Case Report and Review Sangita Deepak Kamath, Neeraj Jain, Saurabh Pathak, Ba...
-
BACKGROUND AND PURPOSE: Lesion load is a common biomarker in multiple sclerosis, yet it has historically shown modest association with cl...
-
Abstract The development of focused ion beam-scanning electron microscopy (FIB-SEM) techniques has allowed high-resolution 3D imaging of n...
-
Vol.48 No.2 from #AlexandrosSfakianakis via Alexandros G.Sfakianakis on Inoreader http://ift.tt/1S2Z7n2 via IFTTT
Δεν υπάρχουν σχόλια:
Δημοσίευση σχολίου